1. Field of the Invention
This invention relates in general to a coding device for printed circuit cards which are insertable into a printed circuit card rack and which are provided with a plug connection connector.
2. Description of the Prior Art
It is known to attach coding strips or rails to the plug connection connectors of insertable printed circuit cards and the coding strips or rails are provided with projections which point in the plug-in direction. A cooperating coding strip or rail is attached to the associated cooperating plug-in means and the cooperating coding strip or rail is provided with the depressions which mate to the projections. The form or arrangement of the projections and respectively the depressions differ for different printed circuit cards. This assures that the printed circuit cards are inserted into the printed circuit card rack at the right location.
There are disadvantages in the prior art type of arrangements in that individual codings do not become effective until the printed circuit card has been nearly entirely inserted into the rack and, thus, no visual control is obtained as to whether the proper printed circuit card has been selected. Also, the printed circuit cards require considerable force for plugging them into the printed circuit card rack and the codings are substantially stressed when the plug type connections engage and they can be damaged.